For aircraft designed for hypersonic travel (i.e., travel at several times the speed of sound), the shape of the aircraft body is very important. In traveling at such high speeds, pressure from impacted air molecules may build up in front of aircraft forward-facing surfaces, resulting in a shockwave.
For the sake of aerodynamic efficiency, wings of some hypersonic aircraft are designed to ride on this shockwave. The shockwave forms a region of pressurized air behind it under the aircraft. The shockwave is a very thin surface in the air that trails from the wing leading edge aft and it dissipates behind the vehicle. To ride the shockwave, the leading edge of the aircraft should be sharp and have a combination of sweep and deflection angles small enough to permit a shockwave to remain attached on the leading edge for the mach number of interest. The attached shockwave then traps all of the pressurized air under the vehicle rendering this kind of design more aerodynamically efficient. This kind of a wing design is called a waverider.
Another issue in the design of hypersonic aircraft is the shape of inlets for scramjets or other propulsion devices that use ambient air (as opposed to rocket engines or other self-contained propulsion devices). Although the aircraft and its inlets operate in a three-dimensional space, inlets may be modeled as two-dimensional openings perpendicular to a chosen axis. Two dimensional inlets can be designed to operate quite efficiently over a range of supersonic speeds. However, two dimensional inlets may not be as efficient as three dimensional inlets at hypersonic speeds. Therefore, there is a need for a method for designing three-dimensional inlets for hypersonic aircraft to provide for efficient engine operation without detracting from the aerodynamic efficiency of the wings of the hypersonic aircraft.